On October 10, the US Navy carried out yet another freedom of navigation operation (FONOP) against China’s claims in the South China Sea.

The USS Chafee, a US Navy Arleigh Burke Class guided missile destroyer, conducted what the Pentagon said were “normal maneuvering operations” in China’s claimed 12 nautical mile territorial sea projected from its 1996 claimed straight baselines that encompass the Paracel Islands.

It was the Trump administration’s fourth FONOP challenging what the US says are illegal Chinese claims in the South China Sea. As usual, China vehemently protested the probe, sent warships and planes to observe the destroyer and requested it to leave its waters.

Given China’s angst and the potential for confrontation and conflict, are such provocative probes legally necessary?

The 1983 US Oceans Policy provides overall guidance for FONOPs. It states that the US “will not … acquiesce in unilateral acts of other states designed to restrict the rights and freedom of the international community.” In turn, the Pentagon says that FONOPs are necessary to demonstrate such non-acquiescence.

But what is legal acquiescence in such a situation, and is it necessary to kinetically demonstrate non-acquiescence through warship challenges?

Acquiescence occurs when a state knowingly does not raise any objection to the infringement of its rights while another state acts in a manner inconsistent with its rights. The doctrine infers a form of “permission” that results from silence or passiveness over an extended period of time.

The USS Nimitz, USS Kitty Hawk and USS John C. Stennis Carrier Strike Groups transit in formation during a joint photo exercise during exercise Valiant Shield 2007 in the Pacific Ocean in this August 14, 2007 handout photo. Mass Communication Specialist Seaman Stephen W. Rowe/U.S. Navy/Handout via REUTERS
US Carrier Strike Groups transit in formation during Valiant Shield exercises in the Pacific Ocean in a file handout photo. Photo: US Navy via Reuters/Stephen Rowe

A similar doctrine to acquiescence is known as “estoppel”, which may arise when “one party gives legal notice of a claim, and the second party fails to challenge or refute that claim within a reasonable time.”

No country should acquiesce to claims that it considers illegal. But non-acquiescence may be effectively and sufficiently demonstrated by verbal and written diplomatic communiqués. The diplomatic option seems to be sufficient for nations, including maritime powers, whose rights the US claims to be protecting.

They generally use verbal or written communiqués to publicize their official positions regarding claims with which they disagree rather than employ ‘gunboat diplomacy.’ This is arguably one reason why US allies Australia, Japan and the Philippines have so far rejected US requests to join its FONOPs challenging China’s claims.

Jonathan Odom, a former US Oceans Policy Advisor in the Office of the Secretary of Defense, worries that non-kinetic action could be interpreted as acquiescence and that “Acquiescence by others poses a risk of legitimizing the coastal state’s excessive claim – if not as a matter of law, then at least in effect.”

For Odom and the Pentagon, FONOPs are necessary to demonstrate non-acquiescence. But Odom also seems to acknowledge that diplomatic protest alone may be sufficient to establish legal non-acquiescence.

The US State Department’s publication Limits in the Seas 117 makes crystal clear its official legal position regarding China’s closing baselines around the Paracels that were the target of the October 10 USS Chafee FONOP.

It states that according to the UN Convention on Law of the Sea (UNCLOS) – which the US has not ratified – no country would be allowed to establish straight baselines enclosing the entire Paracel Island group.

FILE PHOTO: Soldiers of China's People's Liberation Army (PLA) Navy patrol at Woody Island, in the Paracel Archipelago, which is known in China as the Xisha Islands, January 29, 2016. REUTERS/Stringer/File Photo
China’s People’s Liberation Army (PLA) Navy patrol at Woody Island in the Paracel Archipelago on January 29, 2016. Photo: Reuters/Stringer

The US has also repeatedly challenged operationally, as well as verbally and in writing, many other Chinese claims in the South China Sea.

These include Beijing’s claims to excessive straight baselines elsewhere; jurisdiction over airspace above its exclusive economic zone (EEZ); domestic law criminalizing survey activity by foreign entities in the EEZ; and, most frequently, China’s requirement of prior permission for innocent passage of foreign warships through its territorial sea. The State Department’s Limits in the Seas 112 clearly disputes most of these claims – in detail.

Refraining from ‘in your face’ use of warships in favor of diplomatic protest is more consistent with the UN Charter. It requires that “[a]ll Members shall settle their international disputes by peaceful means in such a manner that international peace and security, and justice, are not endangered.”

Use of warships to challenge claims could be interpreted as a threat of use of force, which is also a violation of the UN Charter. Indeed, according to William Aceves of the California Western School of Law, “the notion that states must take action which may lead to a violent confrontation or lose their rights under international law is inconsistent with the most basic principles of international law.”

If other countries follow the US’ example, every country that can and wants to – think North Korea or Iran – employ threats of use of force to demonstrate their legal position regarding maritime disputes would do so.

Russia or China or a coalition of countries could elect to kinetically challenge US assertions of navigational rights under UNCLOS, including transit passage and archipelagic sealanes passage or certain military activities in the EEZ, because the US is not a party to the convention.

The aircraft carrier USS Carl Vinson transits the South China Sea. Photo: US Navy handout via Reuters
The USS Carl Vinson aircraft carrier transits the South China Sea. Photo: US Navy Handout via Reuters

Does the US really want to go down this legal and political path?

There are also problems with US operational assertions of the Law of the Sea in the South China Sea that go beyond the fact that it has not ratified the package deal agreement that it claims to be enforcing.

Unlike in the Paracels, China and other claimants have not declared baselines in the sea’s contested Spratly chain of islands. Thus there is no technical claim by China or any other claimant state to the territorial seas around the features they claim and occupy.

As such, US FONOPs in the Spratlys are pre-emptive challenges to potential claims. For claims that have not yet been made, it would seem that operational challenges are beyond normal international practice – to say the least.

Given the political costs, and even if the US still felt the need to kinetically challenge China’s claims, why does the US Navy deem it necessary to repeat specific FONOP challenges to specific claims, as it often does?

According to a US Navy spokesperson, FONOPs are not “about any one country, nor are they about making political statements.” Despite such denials, it appears to many that the main reasons behind continued US FONOPs against China are political. Indeed, some say that the FONOPs are designed to “…reassure America’s allies and partners in the region of America’s commitment…”

To China, US FONOPs are unnecessary, especially the recurring redundant ones. So, again, are they really worth the risk of confrontation and conflict?

The US may wish to re-evaluate the necessity of its FONOP program –especially pre-emptive and redundant FONOPs – that unnecessarily provoke China. If there is any doubt, the US should err on the side of comity rather than hostility and antagonism – especially regarding a matter perceived as a ‘core interest’ by a major power whose support it wants to meet other US national security objectives.

Mark J Valencia is an internationally known scholar, analyst and consultant focused on maritime policy issues in Asia, and an Adjunct Senior Scholar at the National Institute for South China Sea Studies in Haikou, China.